1. Field of the Invention
The present invention relates to a wire laying-out apparatus for automatically laying out electric wires on a wire laying-out plate. More particularly, the present invention relates to a wire laying-out apparatus for laying out electric wires on a wire laying-out plate so as to manufacture a wiring harness.
2. Description of the Art
A wiring harness mounted on an automobile or the like is constructed by bundling electric wires, which differ in color and thickness, cut to predetermined lengths. The wiring harness has flexibility and has a long narrow and complicatedly branched structure. At the time of manufacturing the wiring harness, a wire laying-out plate is used. The electric wires are laid out in a predetermined configuration on the wire laying-out plate.
A wire laying-out apparatus is disclosed in Japanese Patent Publication No. 46488/1985 and Japanese Patent Laid-Open Gazette No. 221813/1989 as the prior art of interest to the present invention.
In the wire laying-out apparatus disclosed in Japanese Patent Publication No. 46488/1985, a wire laying-out head 201 comprises a plurality of wire holders 202 for, each for holding an electric wire W, and a rotating plate 203 for rotating the plurality of wire holders 202, as shown in FIG. 15. The rotating plate 203 is rotated to select the desired wire holder 202. The wire laying-out head 201 is moved along an X-axis 204 and a Y-axis 205, to lay out the electric wire W held in the selected wire holder 202 on a wire laying-out plate 206.
The wire laying-out apparatus disclosed in Japanese Patent Laid-Open Gazette No. 221813/1989 as the other prior art is shown in FIG. 16. This wire laying-out apparatus uses the same wire laying-out plate 211 as that in the present invention. Specifically, the wire laying-out plate 211 comprises a plurality of clamps 200 on one side extending in the X direction. A plurality of wire holders 212, each for holding an electric wire W, which face the clamps 200 and are arranged in the X direction are provided in the vicinity of the wire laying-out plate 211. At the time of laying, the wire holders 212 are moved along an X-axis 216, to oppose the wire holder 212 to be selected to the wire laying-out head 213. At the same time, the wire laying-out head 213 is moved toward the wire holders 212 along a Y-axis 215, to hold the wire holder 212 opposed thereto. Further, the wire laying-out plate 211 is moved along an X-axis 214, to oppose the desired clamp 200 to the selected wire holder 212. The forward end of the electric wire W held by the selected wire holder 212 is clamped by the clamp 200 opposed thereto. Thereafter, the wire laying-out head 213 is moved in the direction of the Y-axis 215, and the wire laying-out plate 211 is moved in the direction of the X-axis 214, to lay out the electric wire W on the wire laying-out plate 211.
In the wire laying-out apparatus in the prior art, the electric wire is tangled at the time of replacing the electric wire, and it takes time to replace the electric wire, so that it takes time to lay out the electric wire.
More specifically, in the wire laying-out apparatus shown in FIG. 15, the rotating plate 203 is rotated, to select the desired wire holder 202 out of the plurality of wire holders 202. The wire holder 202 is rotated by rotating the rotating plate 203. If the number of wire holders 202 is increased, the electric wire W held in each of the wire holders 202 is easily tangled at the time of rotation. If the electric wire W is tangled, the laying operation is interrupted. Therefore, the speed of the laying operation is not satisfactorily increased. Particularly when the number of types of electric wires to be laid out is increased, this problem is noticeable.
In the wire laying-out apparatus shown in FIG. 16, when the electric wire to be laid out is replaced, the wire laying-out head 213, the wire laying-out plate 211 and the wire holder 212 must be respectively moved to predetermined positions where the electric wire is replaced along the Y-axis 215, the X-axis 214 and the X-axis 216. When the electric wire is replaced, the movement of the wire laying-out head 213, the wire laying-out plate 211 and the wire holder 212 from the position where laying is terminated to the position where the electric wire is replaced is indispensable, so that it takes time to replace the electric wire.